(1) Field of the Invention
The present invention relates to a variable resistor, in particular to the construction of a sliding member incorporated in a chip-type semifixed variable resistor capable of facilitating adjustment of a resistance value by a driver.
(2) State of the Prior Art
FIGS. 8 through 10 show a conventionally well-known chip-type semifixed variable resistor.
In this variable resistor, a resistor 2 of a substantially circular arc shape is provided on a substrate 1, and a tubular portion 8a of a collector terminal 8 at a central hole 1a of the substrate 1 is caulked to rotatably fix a sliding member 3.
The sliding member 3 has a contact portion 4a on an arm portion 4 formed in the shape of a circular arc, some part of the circumference thereof being in contact with the resistor 2. A driver groove portion 5 is provided to enable a driver for slot-headed screws (shapes corresponding to a Phillips head driver are also available) to adjust the resistance value. Reference numerals 2a designate the external electrode connected respectively to both ends of the resistor 2.
In the semifixed variable resistor with the above-described construction, the driver groove portion 5 of the sliding member 3 is approximately 0.5.about.0.6 mm in width (W), 2.2.about.2.6 mm in length (L) and the gap between the driver groove portion 5 and adjusting driver approximately 0.1.